Problem: Which of these numbers is composite? ${3,\ 7,\ 19,\ 35,\ 83}$
A composite number is a number that has more than two factors (including 1 and itself). 3, 7, 19, and 83 each have only two factors. The factors of 35 are 1, 5, 7, and 35. Thus, 35 is the composite number.